American journal of obstetrics and gynecology
-
Am. J. Obstet. Gynecol. · Sep 1990
Acute fetal hemodynamic alterations after intrauterine transfusion for treatment of severe red blood cell alloimmunization.
One of the compensatory hemodynamic mechanisms seen in the anemic human fetus is an increased cardiac output. With Doppler techniques, cardiac output was measured in 21 fetuses before and immediately after 38 intrauterine transfusions for severe red cell alloimmunization. Umbilical venous pressures were measured before and after transfusion; amniotic fluid pressure was also quantitated. ⋯ A calculated mean increase in the fetoplacental volume of 18% in conjunction with an increase in umbilical venous pressure would indicate that cardiac preload was increased. We propose that intravascular intrauterine transfusion leads to an increased cardiac afterload, possibly by increasing blood viscosity. The fetal heart responds to the increased afterload by a decrease in stroke volume, leading to a fall in cardiac output.
-
Am. J. Obstet. Gynecol. · Sep 1990
Magnesium sulfate and promethazine do not interact to cause hypotension in gravid ewes.
The purpose of this study was to determine whether magnesium sulfate and promethazine interact to cause hypotension in gravid ewes. Fifteen experiments were performed in five chronically instrumented animals between 125 and 130 days of timed gestation (term = 145 days). In one group of experiments each animal received magnesium sulfate (4 gm intravenous bolus followed by 4 gm/hr intravenous infusion) then promethazine (50 mg intravenously). ⋯ Maternal and fetal arterial blood gas and acid-base values did not change in any group, except that there was a small, near-significant decrease (p = 0.06) in fetal pH 10 minutes after promethazine was given in the magnesium sulfate-promethazine group. We conclude that magnesium sulfate and promethazine did not interact to cause maternal hypotension in normovolemic gravid ewes. However, promethazine increased maternal heart rate and blunted the increase in uterine blood flow associated with magnesium sulfate.
-
Am. J. Obstet. Gynecol. · Sep 1990
Comparative StudyA comparison of the effect of epidural, general, and no anesthesia on funic acid-base values by stage of labor and type of delivery.
The effect of epidural anesthesia on neonatal acid-base status, before, during, and after labor, was determined by review of funic blood-gas values from 142 women with normal term pregnancies and normal fetal heart rate patterns. Funic acid-base parameters were compared by type of anesthesia when stratified by mode of delivery (vaginal, cesarean section in the active phase of labor, or elective cesarean section). ⋯ Patients who had elective cesarean section with epidural anesthesia had funic acid-base values similar to women who had general anesthesia. Epidural analgesia-anesthesia offers no clear advantage to the uncompromised term fetus.